AWS EC2 Flask Application for S3 Bucket Content Listing

This project demonstrates setting up a Python-based Flask application on an AWS EC2 instance to interact with an S3 bucket. The application provides endpoints to list the contents of an S3 bucket and its directories.

Steps to Set Up the Application

import boto3

app = Flask(__name__)
s3 = boto3.client('s3')
BUCKET_NAME = 'list-bucket-content-demo'

@app.route('/list-bucket-content/<path:subpath>', methods=['GET'])
@app.route('/list-bucket-content', defaults={'subpath': ''}, methods=['GET'])
def list_bucket_content(subpath):
  prefix = subpath.strip('/') + '/' if subpath else ''
  response = s3.list_objects_v2(Bucket=BUCKET_NAME, Prefix=prefix, Delimiter='/')

  contents = []
  if 'CommonPrefixes' in response:
      contents.extend([cp['Prefix'].rstrip('/') for cp in response['CommonPrefixes']])
  if 'Contents' in response:
      contents.extend([obj['Key'].replace(prefix, '') for obj in response['Contents'] if obj['Key'] != prefix])

  return jsonify({'content': contents})

if __name__ == '__main__':
  app.run(host='0.0.0.0', port=5000)

1. Launch an EC2 Instance

• Create an EC2 instance with a suitable AMI (e.g., Ubuntu 20.04).
• Ensure it has an appropriate security group with necessary inbound and outbound rules.

install sudo apt install python3-pip -y
pip install flask boto3
create s3-app.py file

2. Attach an IAM Role to EC2

• Create an IAM Role with the AmazonS3FullAccess policy.
• Attach this role to the EC2 instance.

3. Configure AWS CLI

• Log in to the EC2 instance via SSH.
• Run the following command to configure AWS CLI:

  aws configure

``

4. Create S3 bucket And give Policy

    "Version": "2012-10-17",
    "Id": "Policy1735567338835",
    "Statement": [
        {
            "Sid": "Stmt1735567337153",
            "Effect": "Allow",
            "Principal": "*",
            "Action": "s3:GetObject",
            "Resource": "arn:aws:s3:::taskwalibucket/*"
        }
    ]
}

Some Activity

 ec2 launch
 create role with s3fullaccess policy and attach to the ec2
 aws configure
 create bucket and file structure in bucket
 install sudo apt install python3-pip -y
 pip install flask boto3
 create s3-app.py file
 Run the Service >>  python3 app.py
 Add an inbound rule to allow traffic on port 5000
 Test the Service:
curl http://<EC2_PUBLIC_IP>:5000/list-bucket-content
curl http://<EC2_PUBLIC_IP>:5000/list-bucket-content/dir1
Set Up as a Systemd Service
sudo vi /etc/systemd/system/list-bucket.service

Description=S3 Bucket HTTP Service
After=network.target

[Service]
User=ubuntu
WorkingDirectory=/home/ubuntu
ExecStart=/usr/bin/python3 /home/ubuntu/app.py
Restart=always

[Install]
WantedBy=multi-user.target
Enable and Start the Service
sudo systemctl daemon-reload
sudo systemctl enable list-bucket.service
sudo systemctl start list-bucket.service